How popular is Terushka?

Terushka is an uncommonly occurring given name for females. Terushka is an uncommon surname too for both adults and children. (2000 U.S. Demographics)

Which version is better?

with its source form and related girl names. Teresa(#665 a year ago), Teressa, Teresia and Teresita are the prominent alternative forms of Terushka (not ranked) appearing in the Top 2000. Other variants, like Teresina, are seldom used. Usage of these relations of Terushka was widespread among parents 6 decades ago (median #1022) and is now significantly lower, with the form Teresa falling out of fashion. (2015 U.S. SSA Records)